1. Field of the Invention
The invention relates to a two-part piston for an internal combustion engine.
2. The Prior Art
A two-part piston for an internal combustion engine is known from German Patent Application No. DE 10 2005 060 548 A1; it consists of an upper part having a pin disposed coaxially on the underside of its piston crown, which pin has an outer thread, and of a lower part having an expansion sleeve formed onto the crown part, which sleeve is disposed coaxially, radially on the inside, and can stretch elastically in the axial direction. When the upper part is screwed together with the lower part, the pin is introduced into the expansion sleeve, and afterwards, the nut is screwed onto the pin, which stretches the expansion sleeve in the axial direction. It is a disadvantage, in this connection, that during engine operation, a force that is directed axially can be exerted onto the expansion sleeve, which force exceeds the stretching limit of the expansion sleeve material, and leads to permanent longitudinal expansion of the expansion sleeve and thus to loosening of the screw connection between the upper part and the lower part of the piston.